In plain language, fracture is a break in a bone, and it usually takes place from external violence. The fracture is simple when the bone is broken at one part, and there is no other injury; compound, when in addition to the fracture there is a wound of the soft parts communicating with the fractured bone; comminuted, when the bone is broken into numerous fragments. In the dog, the same fracture is often both compound and comminuted.

Any bone may be broken, but the accident most commonly befalls the bones of the fore leg, those of the hind leg, the thigh bone, the arm bone, in the order of frequency here stated. Several of the small bones, such as the metatarsal, or the metacarpal bones, may be broken by the same force at the same time. The long bones, as the bones of the legs and the ribs, are the most liable to be broken by external violence; the flat bones, or those of the skull, the least so. Fracture may be known -

1. By the deformity of the part injured. Thus, a broken leg is bent, shortened, or twisted; when the skull is fractured, there may, or may not, be depression of the broken bone. The displacement of the bone on which the deformity depends, is caused by the action of the muscular fibres attached to the broken parts, or by the action of the blow, as when a portion of the skull is driven in.

2. The natural movements are altered. The dog cannot move the limb as usual; perhaps all movement is impossible on his part. But the limb can be moved by the surgeon to an extent, and in a direction, that are not natural.

3. A crackling sound is heard when the broken ends are adjusted, and rubbed one on the other. The symptoms cannot be made out unless the ends are first brought into contact - this is obvious. When a rib is broken, this sound is heard during the action of respiration. In some cases, from the peculiar direction of the break, or from the particular bone broken, this symptom is wanting; it is most marked in fracture of the long bones.

4. The general symptoms are pain, swelling, heat, helplessness of the limb, etc. In the dog, simple fractures are not followed by much constitutional disturbance, but compound fractures induce great irritation and inflammation.

Fractures are repaired by the effusion of lymph, which becomes converted into either fibrous tissue or cartilage, and then into bone. The ends are thus firmly cemented together.

The principles of treatment are, -

1. To reduce, or set the fracture, - place the broken bones in their natural position. The upper fragment is to be held steadily in one hand, whilst the lower is extended until the limb acquires its natural shape and length.

2. To keep the limb in its natural place, and to prevent the action of the muscles which would, by contracting, disturb the fracture. For these purposes, splints are used of various materials, and bandages. Gutta percha, cut into slips of the proper length and width, make capital splints. Dipped into warm water, these splints are softened, and easily adapt themselves to the shape of the leg. The hair of the leg will act as a pad, and prevent any injury from the pressure of the splints when they become hard. In some cases, it is advisable to bandage the leg before applying splints, for the purpose of keeping down swelling. A bandage should be applied over the splints. Layers of old linen dipped into thick starch, form, when dry, a light and firm bandage, and give excellent support to the limb. Wadding should be previously used to fill up hollows. Care must be taken not to bandage too tightly, otherwise grave consequences will ensue, - much pain, swelling, perhaps gangrene. Even when the limb is properly bandaged, some swelling will come on in the foot. The bandage should then be slightly slackened.

In fracture of a rib, denoted by depression at the site of injury, and by grating during respiration, the treatment is to encircle the trunk by a bandage, so as to diminish the movements of the rib - to keep the dog confined, for the same reason, exertion increasing respiration - and to feed on a low diet. The displaced fragments may irritate the pleura and lungs, and set up dangerous inflammation. This complication should not be overlooked.

When the skull is fractured with depression, the brain and its membranes are apt to suffer. Professor Simonds has put on record a case of this kind. Head symptoms followed a depressed fracture caused by a quoit hitting the dog's skull. The depressed bone was raised and the dog did well.

Arnica lotion* is invaluable in fractures, as in all injuries. It should be used to the part three times a-day, completely saturating the bandages, etc., so that it may penetrate to the skin.

Absolute rest is indispensable to perfect union; hence, the dog should be confined in such a way as to prevent all use of the injured limb until recovery is completed. He should be muzzled to prevent him from biting off the bandage. In some cases the bones do not unite properly, and it may be expedient to give the dog exercise, or allow him to roam about, as the rubbing of the broken ends will excite some degree of inflammation and exudation, followed by perfect and firm union of the broken ends.

* See Appendix.

In compound fracture, it is necessary, in the first place, to remove all loose splinters or fragments of bones, and to saw off any sharp point that may protrude through the wound, provided it be evident that union will not take place unless these means be resorted to. Then the limb should be set, and bound up with splints and bandages.

In some cases a false joint remains after fracture through the non-union of the broken bone. This may happen when the fracture has not been properly set, or when it has been disturbed or moved by muscular action, or when the limb has been carelessly bound up, or when the reparative processes have been inadequate to perfect union from some constitutional defect. The ends are united by cartilage, instead of by bone; the limb is weak, and there is obviously some extent of movement where the bone was broken.

Aconitum, or Arnica, should be given if the injury be severe, and attended with feverishness, etc.